United said they were “delighted to announce a fee has been agreed with Everton” and the move was “subject to a medical & personal terms”.

It is believed that United will pay £75m up-front plus £15m of add-ons and Wayne Rooney will move to Goodison Park in the opposite direction.

The feeling at Stamford Bridge is that Lukaku’s agent, Mino Raiola, wants him to go to United while the player himself would prefer a move to Chelsea.

Sources in London indicated the decision was down to Lukaku, choosing between suiting his agent’s agenda or a sporting one to satisfy his long-held desire to return to Chelsea, who originally signed him from Anderlecht for £18m in August 2011.

But Lukaku is already in Los Angeles, where he has been training with prospective United team-mate Paul Pogba and is expected to undergo a United medical ahead of their pre-season US tour.

Blues boss Antonio Conte is understood to have become frustrated at the prospect of missing out Lukaku, who had been his principle target for a new striker this summer.

Conte is understood to want to sell Diego Costa this summer, with Atletico Madrid interested in taking the player back to Spain.

All the while, Alvaro Morata remains at Real Madrid, having seen United have a number of offers for him rejected earlier this summer and aware that Chelsea have also been interested in his services.